1. Field of the Invention
The present invention relates to a gas concentration adjusting agent, gas concentration adjusting method, and gas concentration adjusting system, and in particular to a gas concentration adjusting agent that conveniently brings about a low oxygen concentration environment with an oxygen concentration of no more than 1% and a carbon dioxide concentration of between 3 and 7%, for example, an ischemic environment which is necessary for basic research intended to study damage in various organs and viscera at the molecular level during ischemic conditions which prevail in the absence of sufficient circulation of blood to organs and viscera in the course of surgery, cardiac arrest, and organ transplants, as well as to a method and a system for adjusting gas concentrations using this agent.
2. Description of Related Art
A conventional method primarily used to create a low oxygen concentration environment to test cultured cells in ischemic environments has been to connect a vacuum pump and a cylinder filled with a mixed gas consisting of nitrogen and carbon dioxide having a regulated carbon dioxide concentration to a pressure-tight sealed container serving as the culture container, and to repeatedly suction off the gas inside the aforementioned sealed container and supply the mixed gas, so as to place the interior of the container under carbon dioxide-containing nitrogen.
However, this method for forcible gas displacement using the aforementioned pressure-tight sealed container suffers from drawbacks such as the need for large-scale equipment, troublesome and complicated handling, and the need for equipment maintenance. Particularly in the case of tests which undergo changes in the state of the cultured cells over time, gas displacement is required for several containers. Problems that result are the time-consuming nature of the enterprise and the difficulty in establishing uniform test conditions.
Methods involving the use of agents for adjusting the culture environment have also been employed, and anaerobic culture agents which are used to culture anaerobic bacteria, such as "Gaspack" (by BBL) and "Anaeropack" (by Mitsubishi Gas Chemical Company Inc.), have been used as such agents for adjusting culture environments.
However, methods involving the use of these agents for adjusting culture environments have also been plagued with problems such as those given below.
When "Gaspack" is used, for example, water must be added, a catalyst must be prepared, and so forth when it is first used. Furthermore, the rate at which the oxygen is removed is not consistent, making it difficult to achieve uniform culture conditions.
When "Anaeropack" is used, on the other hand, the carbon dioxide concentration in the culture environment increases, leading to drawbacks in that the influence of the carbon dioxide, which continues to dissolve into the culture medium, lowers the culture pH and affects cell culture.